Battery to power most of your home coming soon?

[jpiniero]

So what's the point of having a home battery?

So you can use Solar to get off the grid.

 

[phucheneh]

For someone who knows something about solar panels: What kinda cost would you be looking at, to say, cover, say 500sqft with panels? I'd say that would equate pretty well with decent coverage on the roof of an average home, no? I'm guessing just a couple 10x10 arrays (round it to 250, I guess) would be outside of most people's reach, even.

IIRC, last I heard was you could generate (ballpark) about a watt per square foot. So 500sqft is half a kilowatt. For...maybe 6-8 hours a day on average? Depends on weather at your location, cover from trees and structures...not to mention how your roof is designed.

So the average ATOTer could probably run two computers for most of the time he's awake, at best. One if he's gaming. 500w wouldn't run ANY major appliances, other than at idle (i.e. fridge when the compressor is off).

Energy storage doesn't really seem like the problem here.

 

[DrPizza]

Something like this is going to be needed if Solar is going to go anywhere since it's pretty much inevitable that the utilities are going to stop net metering eventually or seriously curtail how much you can save by sending power to the grid.

I don't think it's the utility's choice. I believe it's regulated by the government

So when do we switch to DC-power in the home.

We don't. Arcs with switching is a problem. AC is safer.
https://www.youtube.com/watch?v=Zez2r1RPpWY

I would be happy if they made a conversion kit that had the electronics and volt conversion and regulation that would allow us to throw say 12-20 car batteries for 2-4 years to do the same function. I bet its gonna be MUCH cheaper than what they what to do because those batteries are not cheap.

Deep cycle batteries, not car batteries. Boat batteries. I suppose it's useful to have a bank of batteries in case of a power outage. But, it's far more logical to insert any extra energy produced during the day into the grid - and then get power from the grid at night when the solar isn't producing anything. Reason: during the day, more power is used as a result of industries. Saving your own energy isn't 100% efficient. That is, if you produce 10 excess kilowatt hours during the day, if you save that energy in a bank of batteries, you're only going to be able to use 7 or 8 of those kilowatt hours of energy during the night. Tis far more efficient to insert that 10 kw-hrs into the grid, then get your 10kw-hrs back during the night. Not to mention the required storage space, plus cost of all those deep cell batteries (they're not cheap).

 

[Jeff7]

They would be to a small degree if the F-ing panels were not so damm expensive, I can't understand why everything else from microprocessors to CCD's to RAM all have been vastly improved and plummeted in price in the last 25 years yet no one seems to be able to bring an affordable solar panel to market. Yea, I realize that part of the price is the installation but the killer cost is still the panels themselves.

You an squeeze more than a billion transistors into one square inch.

A single solar cell might be a dozen square inches of semiconductor material.

So what's the point of having a home battery?

Possible substitute for a backup generator, whether it be a noisy gas-fueled unit or a propane one with a sizable tank.

 

[SparkyJJO]

We don't. Arcs with switching is a problem. AC is safer.
https://www.youtube.com/watch?v=Zez2r1RPpWY

This. That video is an excellent demonstration.

 

[skyking]

to take advantage of solar use in the home, they need to develop DC lighting systems. LEDs are DC, and not having to convert back and forth will save energy and money. A big part of the cost of LED bulbs is the build in DC supply.
If your small loads could be DC in the home, a small battery bank/solar panels make sense.

 

[Rakehellion]

So you can use Solar to get off the grid.

So it's just an extension of solar/wind power which have existed for decades. What's new about this technology?

 

[jpiniero]

So it's just an extension of solar/wind power which have existed for decades. What's new about this technology?

Pretty much, but the economy of scale would theoretically make it more economical to completely get off the grid. You'd obviously need a decent sized battery of some sort to be able to do this since you would need power at night and when it's cloudy.

 

[Red Squirrel]

The cost of solar + batteries is or very soon will be less than the cost of grid power...in Germany. But that's without the Tesla Gigafactory.

With the Gigafactory a similar situation has been predicted in the USA for some time.

And as more people do install solar systems it should get even cheaper.

If we had more sun here I'd consider it. Wind would be a better option but even then the wind is very sporadic here and probably not constant enough. I would want to do it so I can be partially off grid though. To me it makes more sense to store as the cost of me to buy 1kwh from the utility is more than what they'll give me for 1kwh. Idealy I could even do both, when my batteries are topped up anything extra I produce from that point then goes to the grid. To save money you get cheaper RV batteries, but take good care or them. Batteries don't just die, they just slowly lose ability to hold a charge. If you keep them topped up with distilled water, don't let them deplete too much you can squeeze more life out of them.

 

[Jeff7]

to take advantage of solar use in the home, they need to develop DC lighting systems. LEDs are DC, and not having to convert back and forth will save energy and money. A big part of the cost of LED bulbs is the build in DC supply.
If your small loads could be DC in the home, a small battery bank/solar panels make sense.

You'll still need to pass the DC through a regulator to get a voltage that the LEDs like, preferably through an efficient constant current regulator.
Or else half-ass it with a current-limiting resistor and hope it works out.

However, DC-DC can at least be done quite efficiently. While really efficient AC-DC supplies can be made, the cost and complexity tends to go up. The first drop is across the rectifier on the input, which will usually drop (input_amps*0.7)watts right from the start. Add in an active bridge with MOSFETs and you'll gain efficiency, but the cost goes up.

If you go with low-voltage DC, the amp draw goes up, and you need heavier conductors. If you go with high-voltage DC......that stuff just sounds scary.

 

[Red Squirrel]

Yeah would need some kind of DC standard or perhaps a fixture standard for DC. Put higher efficiency converters in light fixtures then the bulbs take DC from the socket. Kinda like a ballast for neon tubes.

Or make bulbs so they can work on 170vdc, so all you need to do is rectify and have a capacitor. Basically about 60 leds in series.

A 48vdc standard in homes along with the regular 120vac would be kinda cool but the arc issue may be a safety hazard. Lot of stuff runs on DC and has to be converted at each point of use so it's kinda inefficient. Computers should also move to 48vdc. We are pumping 100's of amps at 12vdc through tiny conductors. Just look at how much power video cards use. They should be made to use 48v instead. They would produce way less waste heat too.

 

[SparkyJJO]

Would they? 12V powers the cards, but nothing on the card (except the fan) actually runs at 12V. Going from 12V down to the 2V or less that the card uses already produces a fair bit of heat at its regulators. Pushing 48V to it would just make that worse.

 

[Red Squirrel]

Would they? 12V powers the cards, but nothing on the card (except the fan) actually runs at 12V. Going from 12V down to the 2V or less that the card uses already produces a fair bit of heat at its regulators. Pushing 48V to it would just make that worse.

Could make it actually run on 48 though instead of needing 2. Not sure how or if that's possible though, like maybe it's just not possible to make semiconductors that can run on a higher voltage. Was not even thinking of that but yeah the 12v probably gets stepped down even more.

 

[WHAMPOM]

Well that's one website that doesn't deserve to get read anymore.

Yes, I'm sure the electric company is terrified of a battery. Because, you know, batteries just make electricity. By magic.

Obviously, 'why they should be afraid of solar panels' would be more accurate...and they're not. At all.

Yes it is. Battery storage is the bottle-neck holding back global adoption of solar panels and putting corporate supplied power out of business.

 

[skyking]

You'll still need to pass the DC through a regulator to get a voltage that the LEDs like, preferably through an efficient constant current regulator.
Or else half-ass it with a current-limiting resistor and hope it works out.

However, DC-DC can at least be done quite efficiently. While really efficient AC-DC supplies can be made, the cost and complexity tends to go up. The first drop is across the rectifier on the input, which will usually drop (input_amps*0.7)watts right from the start. Add in an active bridge with MOSFETs and you'll gain efficiency, but the cost goes up.

If you go with low-voltage DC, the amp draw goes up, and you need heavier conductors. If you go with high-voltage DC......that stuff just sounds scary.

High efficiency solar panels run in the 30~40 volt range. Lighting loads are so small with LED that amperage and wire size really does not come into play. A 36 V battery bank would have minimal charge converting, and is not high enough to give me the DC heebie jeebies.
laptops and TVs or music systems, network gear could all run off a minimally downconverted outlet. Loads are low. DC refrigerators are also a possibility.
They are common in the marine world, and extremely efficient with the juice.
http://www.indelwebastomarine.com/i...gerators/xlarge-fridges-165-271-l/cruise-271/

That unit uses 700 watts a day! It is by no means ideal or big enough or stylish for home use, but the technology is there.
We get power outages every year here in tree country. Some or a few hours, others are days.
If my food was safe, and the light switches worked that is a good part of the comfort things we miss when the power does go down. A couple hundred AH of storage and 1500 watts of panels would do it.
Heating loads, clothes dryers and washers are not practical loads to plan on. I would have a hybrid system that would do the typical grid intertie with excess solar, and do those loads I mentioned above.

 

[WHAMPOM]

Super conductor capacitance storage battery. Fast charge, high capacity, low loss in storage and non-toxic. Add low cost to that and it is a go. Make 50's SciFi real, Shipstone battery and cheap ceramic full spectrum collector. Heinlein's short stories, I think.
What is the problem with wireing a home in 12Volt? LED and DC camper appliances would work out.

 

[phucheneh]

Yes it is. Battery storage is the bottle-neck holding back global adoption of solar panels and putting corporate supplied power out of business.

Bazinga?

 

[TheSlamma]

So when do we switch to DC-power in the home.

You can do it for much of your lighting already

good luck going DC for your microwave or furnace/AC though.

 

[DrPizza]

to take advantage of solar use in the home, they need to develop DC lighting systems. LEDs are DC, and not having to convert back and forth will save energy and money. A big part of the cost of LED bulbs is the build in DC supply.
If your small loads could be DC in the home, a small battery bank/solar panels make sense.

I know that at least for kitchens, the lighting circuit is supposed to be separate from outlet circuits. That would make converting the lighting system to DC reasonably easy. Simply separate that circuit from the AC panel in the house and move it to a DC panel with whatever circuitry is necessary for regulating the voltage to the LEDs. Red Squirrel mentioned something about a 170V DC circuit - Red, look at the video I posted earlier; though I'm not sure what the effect of a smaller current would be on the arcing.

 

[Murloc]

yeah it's an interesting thing to consider. Roof wires are only ever going to be used for lamps anyway.
I don't think there's a standard though? You would have to mod any LED lamp you buy.

 

[Mark R]

Most commercial electronic fluorescent (compact and strip) and LED ballasts are designed to run on DC as well as AC. Note that this means LED lamps and fluorescent lamps with separate ballasts (common in commercial installations, where independent replacement of components is common to reduce operational costs).

This is because battery backed emergency lighting is common in commercial installations, and if you can run the lamps directly on DC, then it saves the cost of a complete dual-conversion UPS system.

 

[Lonyo]

Yes it is. Battery storage is the bottle-neck holding back global adoption of solar panels and putting corporate supplied power out of business.

Actually there's another reason power companies should be afraid of on-property power storage. It reduces their business. But also increased the profits of those who remain in business.

Power requirements for homes and businesses have peak/off peak cycles, with off peak being overnight for both, peak being morning/evening for homes and during the day for businesses.

If you think of the internet, you have say 100 people with 20MBit internet, all feeding onto a 1GBps pipe, which means you are oversubscribed since you require 2GBps peak bandwidth.
With the internet, you can just let people's service degrade if all 100 people want to use their max connection, and everyone suffers slower internet.
Unlike with the internet, where you can just throttle people or have downgraded service, for electricity that's what causes brownouts, and it's why solar doesn't really reduce the need for power generation on the grid because they have to make up the shortfall in the periods where solar isn't available.

By having on-premises storage, you can even out the peaks and troughs of power generation from the GRID, ignoring any implications of renewables on the premises, because you can generate and feed power overnight which reduces the requirements over the peak times, as the property uses the stored power instead.
That means that you don't need as many power stations at all, because your power generation capacity has to meet peak power use currently, but if you can even out peak use using storage, your power generation capacity can be reduced, meaning you can shutter power stations entirely and still have sufficient power generation available.

http://en.wikipedia.org/wiki/Peaking_power_plant
You would eliminate these types of plants entirely.

http://en.wikipedia.org/wiki/Load_following_power_plant
You would also reduce the number of these required as peak output for them would be reduced as the load would be more evenly spread.

That means you can shutter old/inefficient plants and focus on more efficient ones, which is beneficial, as well as enabling more renewable power generation.

 

[twinrider1]

So when do we switch to DC-power in the home.

We don't. Arcs with switching is a problem. AC is safer.
https://www.youtube.com/watch?v=Zez2r1RPpWY

As much as I'd hope we could operate a switch without leaving it half-cocked, I guess we have to design for the worst case situation.
Still, I'd like to see that experiment run at 24vdc. And at a lower voltage, a capacitor across the switch would minimize the arc, assuming it used a modern spring-loaded switch.


Not really making a case one way or the other, just thinking out loud really. We run 12vdc in cars, 48vdc in airplanes without issue. So I'd think we could make it work in a home. How do dc line losses compare to ac/dc conversion losses? Are dc brushless motors worth the added initial expense compared to ac motors?

 

[JEDI]

Tesla plans to sell a home battery this year. You could avoid having to depend on a fuel powered generator in your back yard or property. Save money on your electrical bill maybe? Well depends on the price of the battery I guess.

http://www.theverge.com/2015/2/13/8033691/why-teslas-battery-for-your-home-should-terrify-utilities

I'm still trying to search the net for the cost of recharging this thing from your regular electrical outlets. Or if you even can. Surely you can right? As long as it's cost effective to recharge it that way after it's paid itself off from the purchase price. You can recharge it from solar panels if you're lucky enough to have them.

small compact hydrogen fuel cell?

or some huge ass solar battery buried in your backyard that's been converted from being recharged from the sun to being recharged by an electrical outlet?
(kinda like a computer UPS but big enuf to power the basics in your house for a few hrs.)

 

[Brovane]

I can't tell if Elon Musk actually believes his businesses will be eventually successful and that his dog and pony show is designed to bridge the time gap between now and when that happens or if he knows he is in trouble and is just praying for some sort of miracle.

Either way, stories like these are integral in the way Elon Musk's keeps his businesses afloat.

-KeithP

Yeah it really looks like Elon Musk's businesses are just a dog and pony show.